'82 280CE. Rust bubble breaking through under the rear quarter chrome trim, both sides. Symmetrical, about 12mm diameter each side.
Question: is this a "drill out, treat, fill, paint" job or has it already gone into the inner structure and I am facing a panel cut-and-weld?
Andy - the W123 Coupe rear quarter rust at the chrome trim is one of the two most-common W123 rust failure points (the other is the rear footwells).. cause: the chrome trim is bedded on a foam strip that absorbs water from the door shut and holds it against the bare metal of the trim attachment lip..
If the bubble is 12mm and symmetrical, the rust is in the OUTER skin only at the trim attachment lip. The inner structure (the wheel arch return) typically rusts inside-out from the boot, not from the trim line.
Diagnosis: remove the chrome trim (gently, the clips are brittle at 40+ years). Inspect the lip. If you can pick the metal with a screwdriver, it has gone through. If it's scaly but intact, it can be treated.
Repair pathway:
Best Sydney specialist for W123 chrome-line rust: Tony at Tony's Classic Restoration (Hurstville, 02 9580 3318). He has done 14 W123 coupes in the last 6 years.
Hugo - thanks. Removing the trim this weekend to assess.